The article "Role of secondary metabolites in plant defense mechanisms: a molecular and biotechnological insights" by Richa Upadhyay, Rajesh Saini, Praveen Kumar Shukla, and Kavindra Nath Tiwari provides a comprehensive overview of the roles and molecular mechanisms of secondary metabolites (SMs) in plant defense against both biotic and abiotic stresses. SMs, which are produced in response to stress, act as deterrents, antifeedants, allelochemicals, toxins, or precursors of other metabolites. These metabolites activate various signaling pathways, such as the calcineurin, jasmonic acid, salicylic acid, and phenylpropanoid pathways, to protect plants from pathogens and herbivores. Polyphenolic compounds, for example, enhance resistance by expressing pathogenesis-related proteins and triggering hypersensitive reactions, while flavonoids help sustain plants through changes in auxin transport. The article also discusses how pathogens and herbivores have coevolved to cope with these defense metabolites by detoxifying or converting them into useful products. The review highlights the upregulation and downregulation of genes controlling SM synthesis and the role of enzymes in these pathways. Additionally, it explores the impact of SMs on other organisms through allelopathy and the potential applications of SMs in biotechnology.The article "Role of secondary metabolites in plant defense mechanisms: a molecular and biotechnological insights" by Richa Upadhyay, Rajesh Saini, Praveen Kumar Shukla, and Kavindra Nath Tiwari provides a comprehensive overview of the roles and molecular mechanisms of secondary metabolites (SMs) in plant defense against both biotic and abiotic stresses. SMs, which are produced in response to stress, act as deterrents, antifeedants, allelochemicals, toxins, or precursors of other metabolites. These metabolites activate various signaling pathways, such as the calcineurin, jasmonic acid, salicylic acid, and phenylpropanoid pathways, to protect plants from pathogens and herbivores. Polyphenolic compounds, for example, enhance resistance by expressing pathogenesis-related proteins and triggering hypersensitive reactions, while flavonoids help sustain plants through changes in auxin transport. The article also discusses how pathogens and herbivores have coevolved to cope with these defense metabolites by detoxifying or converting them into useful products. The review highlights the upregulation and downregulation of genes controlling SM synthesis and the role of enzymes in these pathways. Additionally, it explores the impact of SMs on other organisms through allelopathy and the potential applications of SMs in biotechnology.